Note: Arčar is a village located in Bulgaria on the Danube River. It. was an ancient Celtic settlement, then the base for Imperial Rome's Danube fleet. It was the capital of the Roman province of Upper Moesia and a rival to Sofia. The city was busy and thriving when it was destroyed by the Huns in 447 CE. Rebuilt by Emperor Justinian, it was razed by invading Avars in 576.